Is there any API that allows me to check if a Username is in use?

Question

We are creating our own ISV trial provisioning page and using the SignupRequest API to create trials. I can't seem to figure out a way to check for the availability of a username synchronously. Unfortunately, the only way to figure out if a username is taken is to signup and then the user gets a pretty generic failure email with a link back to the wrong trial page (the standard Salesforce trial signup page). I would rather check for the existence of a username while the user is filling out the form if possible. Is there any API that enables this?

Answer 1

No need for an API. Just use synchronous Apex code instead.

Simply create and insert a User in a try and check for the right exception in the catch and always rollback the insert in the finally.

This class should do the job.

public class UserService {
    public static Boolean existsName(String fullUserName) {
        Boolean result = false;

        User user = new User();  
        user.FirstName = 'any';
        user.LastName = 'any';
        user.Alias = 'any';
        user.EMail = 'any@email.com';
        user.Username = fullUserName;
        user.CommunityNickname = fullUserName;
        user.LocaleSidKey = 'en_US';
        user.LanguageLocaleKey = 'en_US';
        user.EmailEncodingKey = 'UTF-8';
        user.TimeZoneSidKey = 'America/Los_Angeles';
        user.ProfileId = [SELECT Id, Name FROM Profile WHERE Name='Standard User' limit 1].Id;

        Savepoint sp = Database.setSavepoint();

        try {
            insert user;
        }
        catch(DmlException ex) {
            if(ex.getDmlStatusCode(0) == StatusCode.DUPLICATE_USERNAME.name()) {
                result = true; 
            }
        }
        finally {
            Database.rollback(sp);
        }

        return result;
    }
}